Series TD. Type TDL Type TDM. Automatic Recirculation Valve for pump protection

Transcription

1 Series TD Type TDL Type TDM Automatic Recirculation Valve for pump protection

2 Series TD The SCHROEDAHL Automatic Recirculation Valve is used for the pump protection of centrifugal pumps Preamble SCHROEDAHL is the largest supplier of Automatic Recirculation Valves in the world. These ARVs, or pump protection systems, are our principal products. During the last 50 years we have supplied more than 50,000 of these valves to satisfied customers all over the world. Features Automatic bypass operation Modulating bypass operation Low maintenance Easy to install Damping of system pulsations Suitable for wide range of fluids Self operated Reduces plant investment and operational costs 2

3 Application The SCHROEDAHL Automatic Recirculation Valve is a high quality automatic solution to protect centrifugal pumps against overheating, instability and cavitation, during zero process flow and low load conditions. If the flow through the system is or falls below a certain level, the bypass system opens automatically and the fluid is recirculated, providing the required minimum flow for the pump. Special operation requirements, low load cases, complicated commissioning situations and the pressure in the bypass line have an impact on the valve design and therefore are typically part of customers RFQ information - SCHROEDAHL can offer solutions at a very high level. The SCHROEDAHL automatic recirculation valve is therefore a high quality, cheaper and easier solution for clean liquid pump protection - more cost effective than a conventional modulating control valve package. Sectional drawing of an Automatic Recirculation Valve type TDM Sectional drawing of an Automatic Recirculation Valve type TDL Fig. 1 Fig. 2 3

4 Operation of the Automatic Recirculation Valves Fig. 3 Fig.4: Type TDL Fig.5: Type TDM 4

5 Operation Range Definition The following two descriptions are typical of the pump protection application: 1. Standard Operation Range Application: The usual operation of pump protection valves is in the load range from 40% to 100% of the rated process flow. The automatic valve will handle the typical time-limited start-up and shut-down phase with modulating bypass control operation. TDM valves at high pressure service may also need an adequate bypass back pressure, e.g. an orifice restriction in bypass line, to prevent cavitation during bypass flow condition. 2. Full Operation Range Application: For high pressure TDM applications that will operate over the full load range from 0 % to 100 % process flow, it will be necessary before placing the order to evaluate special design influences at the valve. Otherwise the application will be classified as a standard range type. For the high load range, depending on the existing bypass pressure level, it may be necessary to increase the bypass back pressure to prevent cavitation, especially when the bypass is in modulating action. Therefore the installation of a special back pressure valve BPV is recommended, to ensure that the bypass pressure level is always at a suitable pressure level (an orifice plate will not work). Operation The outlet main flow controls the check valve and positions it in proportion to the flow. The stem of the check valve transmits the motion via a lever to the bypass. The bypass system regulates the bypass flow in a modulating way and reduces the pressure to the bypass outlet pressure level without cavitation. The full minimum flow is bypassed when the main check valve is seated. The bypass is fully closed when the check valve is in its upper position, thereby allowing full pump flow to the system. Flow sensitive modulating bypass control The check valve moves upwards with increasing main flow and downwards with decreasing flow. The check valve transmits this motion via a lever to the bypass system (Fig. 4 and 5) and therefore controls the bypass flow in a modulating position. Type TDL The TDL consists of the check valve section (Fig. 3) with bypass configuration type L (Fig. 4). The lever controls the position of the bushing, which in turn opens or closes the holes in the control head. The minimum flow is thereby bypassed in a modulating way. Applicable for differential pressures up to 40 bar. Standard with non-return function. Type TDM The TDM consists of the check valve section (Fig. 3) with bypass configuration type M (Fig. 5). The movement of the lever is transmitted via a piston to the multi-stage vortex plug. The minimum flow is then bypassed in a modulating way over several pressure reduction stages. Applicable for differential pressures from 20 bar to 230 bar. The standard TDM design has a built-in bypass non-return function (~2 bar dp level required). 5

6 Manual Bypass Options for type TD Automatic Recirculation Valves Fig. 6 Options A: A1 A2 A3 A4 A5 6

7 Options Information Depending on the plant design or additional requirements, different options for the start-up/warm-up side (A), or for the bypass trim side (B) can be selected. Options A: A typical option is the start-up connection acc. (Fig. A1), to run low pressure flow to the process/ boiler for the start-up process, or to warm-up the neighboring pump/system. Options B: Depending on the plant commissioning condition (dirt, spec. load case, ), a special commissioning bypass trim set can be selected. The valve will then be shipped with the option bypass set and also attached with the original bypass trim set (to be installed after commissioning). Please contact SCHROEDAHL for additional information.. Options A: Additional connection options (on request): A1: Start-up/warm-up above check valve A2: Start-up/warm-up below check valve. A3: Warm-up above check valve. A4: Warm-up below check valve. A5: Degassing Nozzle Options B: Commissioning options for the bypass side (on request): B-TDL: Commissioning bypass internals for TDL valve (bigger clearances, modulating) B-TDM: Commissioning bypass internals for TDM valve (continuous open, fixed flow coefficient, non-modulating, without moving parts) Options B: B-TDL B-TDM 7

8 Valve sizes Standard size from DN 25 (1 ) to DN 300 (12 ). Pressure rating Pressure rating from PN 10 to PN 400 (class to class 2500). Other ratings upon request. Connections Flanges are standard according to EN or ASME. Flanges according to other standards (ISO, BS, JIS, NF) are available upon request. The inlet and outlet connections can also be supplied with welding ends. The bypass connection is always flanged (for inspection purposes). Manual start-up upon request. Draining or warm-up connections are available, too. Materials Standard housing materials: ASTM A105 (Carbon Steel), EN ASTM 316L (Stainless Steel), EN The standard internals of the TD valves are manufactured from stainless steel with a minimum chrome content of 13%. Other forged materials for housing and internals are available upon request. Selection of the seal material is done according to medium and temperature conditions. The housing material is selected according to medium, pressure temperature conditions and customer requirements. Size Code Pressure Class Code Connection Code Configuration Code 05 = DN 25 (1 ) 06 = DN 32 (1 1/4 ) 07 = DN 40 (1 1/2 ) 08 = DN 50 (2 ) 09 = DN 65 (2 1/2 ) 10 = DN 80 (3 ) 11 = DN 100 (4 ) 12 = DN 125 (5 ) 13 = DN (6 ) 15 = DN 200 (8 ) 16 = DN 250 (10 ) 17 = DN 300 (12 ) 1 = PN 10 2 = PN 16 3 = PN 25 (Class ) 4 = PN 40 5 = PN 64 (Class 300) 6 = PN 100 (Class 600) 7 = PN 160 (Class 900) 8 = PN 250 (Class 0) 9 = PN = PN 400 (Class 2500) F = Flanges acc. to EN U = Flanges acc. to ASME S = Welding Ends (not for bypass) J = Japanese Standard B = British Standard V = Vertical Installation H = Horizontal Installation A = Manual start-up connection W = Standard oversized bypass CS = Carbon Steel SS = Stainless Steel SD = Duplex Steel Example TDM116UVW-CS: valve type TDM; 4, class 600, ASME-Flanges, vertical installation, housing material in carbon steel 8

9 Installation Information The Automatic Recirculation Valve should be installed as close as possible to the centrifugal pump discharge, preferably directly on the outlet of the pump. To prevent low frequency shocks caused by pulsation of the medium, the distance between pump outlet and valve inlet should not exceed 5 m with straight pipe run at the inlet. Exceptions have to be reviewed by SCHROEDAHL. Vertical installation is preferred, but horizontal installation is also possible on request. The TDL and TDM valves operate at a low noise level and ensure a high reliability due to their sturdy design. The recommended filter at the pump inlet should have a maximum mesh size of 0.3 to 0.5 mm. For commissioning, we recommend a smaller filter mesh size (e.g. 0,1 mm). Maintenance, Spares and Test Maintenance instructions are available upon request or at Typically we recommend an inspection after commissioning (a gasket set is then needed), and for two-year operation, we recommend a bypass set (one complete bypass unit) for your stock. A complete valve performance test run is recommended to be done together with the original pump. The bypass Kv/Cv value test can be certified at our test facility. Please contact SCHROEDAHL for additional information. To the system Place for BPV or Orifice Straight pipe run 3 x DN As near as possible to the tank ARV Tank Best Distance: zero! or maximum 3m with straight pipe run of 2 x DN No elbow allowed at inlet! Fig. 7 9

10 Parts list Housing Bypass L Bypass Housing assembly Item Description 01 Lower Body 02 Upper Body 03 Stem Guide 04 Guide Bolt 06 Spring 07 Check Valve cpl Check Valve 07.2 Stem 08 Liner or Venturi-Ring 09 Bypass Branch 25 Guide Pin 26 Bolt 27 Bolt 28 Hexagon Nut 29 Hexagon Nut 30 Bypass L Item Description Control Head Lever Pivot Pin Crank Arm Control Bushing Orifice Bushing Spring Bottom Ring 10

11 Bypass M Manual Start-up (Option A1, example) Bypass M Item Description Vortex Bushing Control Head Vortex Plug Lever Pivot Pin Relief Bushing Relief Piston Threaded Ring Bypass Orifice / Cone Glyd-Ring Glyd-Ring Glyd-Ring Manual Start-up Item Description 10 Vortex Bushing 18 Vortex Plug 19 Holder 20 Pin 23 Orifice Plate

12 Sizing and selection Nominal size and pressure class of the Automatic Recirculation Valve should preferably be the same as the outlet of the pump. Notes The following table is only to be used as an indication. Other bypass sizes available upon request. For final valve selection please contact our office. Size Code DN P, R (mm) DN P, R (inch) 1 1¼ 1½ 2 2½ Max. flow P,R for TDL and TDM valves (m 3 /h) Bypass L /M DN (mm) see Fig.4/5 DN (inch) ½ 1½ 2 2 2½ Max. Bypas flow P-B (m 3 /h) Example valve selection Kv = Q min x S.G. p Q min = Minimum flow in m 3 /h, s.g. specific gravity in kg/dm 3 Δp = Differential pressure in bar over the bypass at minimum flow Conditions: Pump DN 100, PN 100, main flow is 180 m 3 /h, required bypass flow is 40 m 3 /h, S.G. is 0.95, Δp is 70 bar at Q min. Selection: a. The main flow is in the range of a valve DN 100. b. The p at minimum flow is 40 bar, this means that we have to select a valve type TDM. c. K v = 40 x 0.95 / 70 = 4.8 m 3 /h, this means a valve DN 100 with a bypass DN 50 can be used as the maximum K v is 5.4 m 3 /h. 12

13 Automatic Recirculation Valve Technical Data Customer: Enquiry no.: Prior reference: Order no.: Project: Data sheet: Quantity: Automatic Recirculation Valve type: Valve inlet DN PN Valve outlet DN PN Bypass outlet DN PN Start-up DN PN Fl.Code.: Installation: vertical horizontal Paint: Start-up above below check valve Mat.-/test certificates: Materials Housing: Internals: Seals: Medium Operating temp. [ C]: S.G. [kg/m³]: Design temp. [ C]: H 0 = m Q M = m³/h H M = m Suction pr. pv bar Q 100 = m³/h H 100 = m Differential pr. (p 1 -p n ) bar Q max = m³/h H Qmax = m Back pressure p N bar Q A = m³/h H A = m Back pressure p A bar Notes: Revision Date Description Name Signature H 0 H M H 50 Rangeability Duty point Q max Head H in m H 100 H Qmax Q M Flow Q in % 13

14 Dimensions EN Size DN R /DN P PN DN B L (mm) S (mm) H (mm) Weight (kg)

15 P = Pump outlet R = Pipeline/ process B = Bypass connection (A = Start-up connection as option) ASME Size DN R /DN P PN DN B L (mm) S (mm) H (mm) Weight (kg) ½" 600 1" " 600 1" ½" 600 1½" " 600 1½" " 600 2" " 600 2" " 600 2½" " 600 3" " 600 4" " 600 5"

16 2016 XYQOM GmbH / rev. 2016_UK_005 SCHROEDAHL GmbH Alte Schönenbacher Str Reichshof-Mittelagger GERMANY Phone Fax schroedahl@circor.com